There are a number of devices which provide an illuminated cup holder, typically in automobiles or theater seating, which aid in using the cup holder in low light situations. There are also various cups that bear a logo or utilize an illuminated or powered graphic, in which the illumination is typically an LED (light emitting diode) or backlit LCD (liquid crystal display) that is powered by a battery. There is a strong market for promotional materials for any particular brand, such as coffee, beer, tea, sports teams, cities, sporting equipment, and many other articles. Each of these entities produces products in which their insignia may be displayed. The products can be pennants, shot glasses, collectible spoons, enameled pins, travel mugs, coffee cups, can openers, decals, and many other articles. Sometimes these are given away or sold inexpensively as a memento of a trip.
A cup which is illuminated, or bears a powered graphic display, which does not require a battery would be very desirable in this product field. Having it be powered by solar power is one option, but solar power is only available when the product is in the sunshine. A novel way of powering the display would be to use the heat or cold from the product itself, such as heat from a hot cup of coffee or the chill of an ice-cold beer, to power the display. The display could be a logo, an interesting phrase, the trademark of a sports team or a company, or other graphics which are typically used in promotional products.